-- Every point on the surface of a globe is the same distance from
one point inside the globe, called the "center".
-- The circumference of any circle on the surface of the globe whose
center is at the center of the globe is (pi) x (the globe's diameter).
-- The total surface area of the globe is (4 pi) x (the globe's radius squared).
-- The total volume inside the globe is (4/3) x (pi) x (the globe's radius cubed).
-- If you draw a triangle on the surface of the globe and add up the three angles
inside the triangle, the sum can be any number between 180 and 540 degrees.
